Specific-gravity balance.



P. E. YOUNG.

SPECIFIC GRAVITY BALANCE. 7

APPLICATION FILED AUG-21, 19H.

Patented June 27, 1916.

-INl/ENTOR WITNESSES A TTURNEY umTE STATES PATENT I omen PHILIP E.YOUNG, OI FAIBHA VEN', MASSACHUSETTS.

sPncImc onAvIrY BALANCE.

Specification or Letters Patent.

Patented Ju e 27, 1916.

I I Application medmu ust 21, 1914. Serial No. 857,829.

' commercial establishments where the specific densities of a largenumber of difi'erent bodies must be determined quickly and with a fairdegree of accuracy.

One of the objects of the invention is to provide such an instrument forindlcating directly on a suitably graduated scale the specific densityof the body with but one bal-' ancing operation; without resort tomathematical computations, and without the necessity of taking anyrefined weighmgs.

Another object of the invention is to provide a device of the'aboveindicated char-' acter which, while retaining all of the advantages of acompact and sensitive'balance, provides for a refined andmlnut'esub-division of the specific density scale spread over a long run.

One means of obtaining these obiects is to i provide a tangent balancecarrying a rela-' tively longpointer movable over a quadrant scale ofrelatively large radius graduated in v numerical values indlcatingspecific densities and in the embodiment of the invention where the armsof the balance are at 135 to each other the numbered graduations are sospaced relative to each otherlthat the tangent of the angle of movementcaused by the buoyant effect of the displaced water on the submergedbody will be equal to 1. Y

.g1 1 where. 9 indicates any of the Values indicating the specificdensities within the range of the instrument. 4

Various other objects and advantages of the invention will be in partobvious from 'an inspection of the accompanying drawin s and in partwill be more fully set forth in the following particular description ofone form of mechanism embodying my invention, and the invention alsoconsists in certain new and novel features of construction andcombination of forth and claimed.

I Inthe accompanying drawingsz-Figure 1 1s a side elevation of aninstrument disclosmg a preferred embodiment of my invention; Fig. 2 isan end elevation of the device shown in Fig. 1; and Fig. 3 is anexplanatory diagramillustrating the mathematics parts hereinafter set ofthe device.

' The instrument illustrated is a sensitive tangent balance including aframe 1 comprising a broad, and referabl hea base plate' 2 fixed towhich is a be in su giiort 3 formed of transversely spaced apartuprights 4 braced adjacent the top by a connectmg spacing rod 5. A-balance beam 6 is pivotally mounted between the uprights 4 and is freeto oscillate in a vertical plane.

The beam is mounted on a horizontally disposed pivot pin 7 journaled inend bearings 8, threaded mto the uprights 4 and providingthe fulcrum Ofor" the balance. The beam comprises a pair of balance arms pro-.jecti'ng on opposite sides of the fulcrum and may extend at any angleto each other, but for determining densities from one to two, adepending angle ofa hundred and thirty-five degrees between the arms hasbeen found "to be the most eflicient HOW? ever, one type of device nowin general use has the arm designed to-form practically a straight anglewith the scale graduated accordingly. One'of the arms 9, hereinafterdesignated as the weight arm, is arranged to be horizontally disposedwhen the turning I moments about the fulcrum are balanced and I acounterbalancing weight W is slidably mounted thereon to and from thefulcrum.

' To provide for a refined adi ustment of the weight and to hold the samin set position relative to the fulcrum the arm is preferably threadedmicroinetrically so that the weight may be rotated thereon to accuratelycounterbalance the body S, the specific density of which is to bedetermined. The

character. A pointer 12 extends radially from the fulcrum, is attachedto the beam to indicate the angle of movement thereof and is maderelatively long so as to magnify this movement. The weight arm may bemade relativelylong and light and the end reduced to form a sharppointer, which arrangement eliminates the necessity of providing aspecial member to form the pointer. The extreme end of the pointer isarranged to move over a suitably curved scale 13' under the influence ofthe buoyant effect of the displaced water containedin a suitablereceptacle 14 when the body S is submerged below the level of the watertherein. The scale is in the form of a quadrant'disposed on the side ofthe support having the weight arm with its lower portion affixed to thebase and arranged so as to extend substantially in the plane of movementof the weight arm and in a curve about the fulcrum as a center. Thescale is provided with a balance mark co positioned thereon in ahorizontal plane containing the axis of oscillation of the balance andopposite the position as-v sumed by the pointer when the weight Wcounterbalances the body S in air. The scale is graduated in proressively increasing numerical values toward the balance mark from onewhich is positioned ninety degrees from the balance mark and at thepoint on the scale opposite the position assumed by the pointer when thedisplaced water entirely supports the weight of the submer ed body.

The ase plate 2 is adjustable vertically so that the one on the scale isperpendicularly below the axis of oscillation of the beam and for thispurpose the plate is 7 -made substantially triangular in plan with whereoais the angle of movement of the one or more'feet along aside thereofwhich is parallel with the axis of oscillation of the beam and with avertically adjustable support, such asa leveling screw 15, positioned inthe angle opposite the-side having the foot and positioned beneath thescale.

The values opposite the graduations on the scale indicate specificdensities and are each equal to the expression tan. oz

pointer in passingfrom the balance mark to the position opposite theparticular graduation, under the action of the buoyant efmeats? fect ofthe displaced water on the submerged body. 1

Should it be desired to construct scale quickly and without thenecessity o accurately spacing the graduations according to the formula,value two can be iplaced forty-five degrees from the one ion the scaleand the intervening are divided with equally spaced graduatlons numberedin correspondingly progressing fractional val-' ues from one to twowhich values will indicate approxlmately the specific densities of thesubmerged bodies when the; pointer swings to the .value under thebuoyant effect of the displaced water. .TlllS equal spacing of thegraduations one part of the scale permits of a simple and readilyconstructed scale for use in determining specific densities of from oneto two with-- out the necessity of accurate relative spacing of thegraduations on the scale in terms of an arithmetic progression and atthe same time the equally spaced readings indicate values suflicientlyaccurate for most com.- mercial requirements.

The beam including the weight arm, the balance arm and the wire forsupporting the body S is balanced about the fulcrum and to facilitatethe construction of a device providing this equilibrium of'forces aboutthe fulcrum when the body and weight are omitted the beam is providedwith a counterbalancing ball 16 extending therefrom above the fulcrum.

In operation, the instrument is placed on a firm support and is adjustedby means of the leveling screw until the pointer is opposite one on thescale when the body arm is free of any weight. The body, the specificdensity of which is to be determined, is suspended in air on the wire11, 6 units of length from the perpendicular passing through the fulcrumand the weight "W is adjusted to such a position, 03 units of lengthfrom the fulcrum in which position of the parts the turning moments onthe beam are balanced about the fulcrum under which conditions thepointer is opposite the balance mark oo on the scale. The body is thensubmerged in water and freed from air bubbles adhering thereto and tothe wire as is usual in operations of this character. The submergedobject will have an apparent loss of weight and the beam will be actedupon by the turning moment of the weight arm to swing the pointer overan angle a into the position on the scale to indicate the specificdensity of the submerged object by the direct reading of the scale.These values on the scale indicate the specific When body S is suspendedon wire 11 .and weight W is moved so that pointer 12 is opposite co Whenbody weight becomes cos. (a 45) 1 cos. a

cos. a+sin. 0:

Therefore a anti-tangent 1 ,or the angle through which the pointerpassesis equal to the angle whose tangent is 1 divided by g-1.

By means of a device of this character the specific density is obtainedby the submer-j sion method which permits of extreme accuracy and theapparent loss of weight ofthe body is in effect definitely ascertainedirrespective of any irregularity'in' the configuration of the body.As-the operation does not involve any weighings the error' usuallyintroduced in ascertaining the weight of the body in terms of someweight y I Where afis the angle of movement of the pointer in passingfrom the balance mark to the position of the. Value on the scale.

units is eliminated and there is also avoided the possible error arisingfrom both subtractlng and dividing operations usual in ascertainingspecific densities by the submersion method.

S is immersedin water its scribed, then the While the. invention hasbeen described articularly with reference to an mstrument intended forcommercial use, it is ObVlOllS that all of the refinements usual in theconstruction of sensitive chemical balances may be employed and thatvarlous omlsslons,

. substitutions and chan es in the'form and details of the device ilustrated and in-its o eration may be made bythose skilled in -t e artwithout departing from the s irit of the invention. For example, if theody f S has a predetermined gravity, then the density of the liquid inthe rece tacle 14 may be directly determined throug the position of thearm 9 merely byproviding the uadrant with, a suitable scale. It is also0 vious that should the arms of the balance have some other relationthan the 135 dehorizontal distance between weight W and theperpendicularthrough the fulcrum and the horizontal distance between thebody S and said per endicular.

Should it e desired to construct a scale for obtaining specificdensities of value higher than those indicated on the illustrated scale,as from 2 to 10, the angle being specific densities by the submersion.

method, comprising a beam with one'of its balancing arms adapted to havethe body,

- the sp'ecificdensity of which is to be deter mined, suspendedtherefrom and the other arm adapted to have a counterbalancing weightcarried thereby, a pointer controlled themovement of said-beam whensubaduations of the scale 7 would be plotted rom the relation of thejected to the buoyant, efi'ect of thedispla'ced i water on the body whensubmerged-therein,- a scale'for said pointer, said scale having a 1 i0balancemark thereon opposite the posit1on assumed'by' the pointer whenthe 'body is balanced by the counterweight and said scale beinggraduated in progressively 'i n v creasing numerical values from thenumeral one located opposlte the pos1t1on assumed by thepointerwhenthebuoyant efi'ect of thedisplaced water balances the weight of. thedisplacing body, toward said balancemark on the scale, each particularvalue heing equal tothe expression 1 tan. a

particular numerical 2'; A tangent balance for use in determinthespeclfic densit so that the weight will be positioned a distance fromthe perpendicular equal tothe' cos. of the-an le of movement of thebalance when the fiody is subjected to the buoyant efi'ect of thedisplaced water on the su merged body and means for measuring thisposition of the weight in terms of specific densities.

3. A. tangent balance for use in determining specific densities by thesubmersion method comprising a beam with one of the balance arms thereofadapted to have the body, the specific density of which'is to be'determined, suspended therefrom and the other arm being screw threaded,a counterbalancing weight adjustable on said threaded arm for movementto and from the fulcrum thereby to balance the body in air,

' a pointer moved with said beam, a scale for said pointer having a markthereon o posite the position assumed by the polnter When saidbeam isbalanced and a second mark opposite the position assumed by the pointerwhen the body is not exerting any meats? force on the balance, saidscale being graduated between said marks with the value one at saidsecond mark and with gradually progressing numerical values extendingfrom this one toward the first vnamed mark and designated to indicatethe specificdensities of the body.

4. In a device of the class described, the combination with a balancebeam including a body arm adapted to have the body, the specific densityof which is to be determined, suspended therefrom and a counterbalancingweighted arm, a pointer controlled by the movementof said beam, a scalefor said pointer, a portion of said scale being graduated in equaldivisions and desi ated with progressing numerical values rom one whichis positioned opposite the position assumed by the pointer when the bodyis not exerting any force on the body arm to. the value two positionedon the scale fortyfive degrees from the value one in a directionopposite to the direction of movement of said pointer when passing fromits position when the balance is in equilibrium toward the positionindicated by the value Signed at New Bedford in the county of Bristoland State of Massachusetts this seventeenth day of August A. D. 1914.

PHILIP E. YOUNG.

Witnesses:

R. A. TERHUNE, FLORA M. LEARY.

